Abstract
Selective transfer hydrogenation of nitroarenes to amines with transition metal nanocatalysts is appealing due to its low-cost, moderate reaction conditions, good activity and excellent selectivity. Single-atom catalysts (SACs) possessing advantages of maximum atom efficiency and particular electronic structure are expected to be more effective for this reaction, yet no report about it. Herein, cobalt single atoms anchored on N-doped ultrathin carbon nanosheets (denoted as CoSAs/NCNS) were produced and demonstrated as an outstanding SAC for selective transfer hydrogenation of nitroarenes to amines with formic acid as hydrogen donor. The turnover frequency (TOF) reached 110.6 h(-1), which was 20 times higher than the best results of cobalt nanoparticles reported in literatures under similar reaction conditions. Moreover, CoSAs/NCNS exhibited excellent selectivity for a variety of nitroarenes bearing other reducible functionalities, such as iodo, cyano, keto, vinyl, alkynyl and ester groups. The findings further highlight the ability and advantages of SACs in heterogeneous catalysis.